The present application relates to semiconductor processing, and more particularly to directed self-assembly (DSA) of block copolymer materials templated by spacers formed by a sidewall image transfer process.
Directed self-assembly (DSA) of block copolymers through physically templating is an emerging patterning technology for generating narrow lines in integrated circuits with smaller pitches beyond the current optical lithographic limit. During the DSA process, block copolymers composed of chemically distinct polymer chains (blocks) that are covalently bonded at their ends self-assemble to form nanoscale structures, often with dimensions in the range of 5 nm to 50 nm, due to microphase separation of immiscible blocks. The DSA pattern generated from the block copolymers can be used as a mask for further pattern transfer into functional materials such as insulating, semiconducting, and conducting materials.
The pitch of the features generated from the DSA pattern is limited by lithography techniques used to print the templates employed to guide the alignment of the block copolymers. The continued scaling of design features in ICs requires the pitch of the templates to be scaled below 80 nm which is below a minimum lithographic pitch can be printed with present lithographic tools. Accordingly, a need exists for improved methods that allow forming nanoscale structures by self-assemble of block copolymers guided by templates having pitches beyond the current optical lithographic limit.